Destruction of the Great Chain

The Destruction of the Great Chain occurred in 1511 when Assassin Ezio Auditore da Firenze used a Greek Fire flamethrower cannon to burn down the seven ships blocking the Great Chain, and used a bomb to blow up the lighthouse which attached the Great Chain to the other lighthouse. The Great Chain sunk underwater, and Ezio escaped with Piri Reis to Cappadocia.

Background
Ezio Auditore da Firenze, a member of the Assassins Order, was sent to kill Captain Tarik Barleti by Prince Suleiman the Magnificent, who believed that Barleti was assisting Manuel Palaiologos' Byzantine restoration movement and that he was fighting against his grandfather, Sultan Bayezid II. Ezio carried out the assassination of the Janissary Captain, but found out that he was innocent when he died, and told Suleiman. As Ezio left, he heard Shehzade Ahmet, the heir apparent of the empire and uncle of Suleiman, tell him that a man had killed Barleti, and that he would hunt him down. Suleiman pretended to not hear of the tragedy, and he told Ezio that a boat was waiting at the docks to take him to Cappadocia.

Battle
However, the Ottoman Navy raised the Great Chain in the Golden Horn to prevent any ship from leaving the city, as they investigated the murder of Barleti. The chain was defended by seven Ottoman vessels, and Ezio became a wanted man. Supplied with a bomb given to him by Yusuf Tazim, a fellow Assassin, Ezio planted the bomb on the base of the Great Chain at a lighthouse, and he used his hidden gun to blow it up, destroying the lighthouse and sinking the Great Chain under the water. Ezio made it to a ship at the docks that had a Greek Fire flamethrower cannon, and he used it to burn down all seven Ottoman galleys, and he rushed over the sinking and burning ships to Piri Reis' vessel, which was leaving harbor. Ezio made it in time, and escaped.

Aftermath
The destruction of the Great Chain and Ottoman Navy weakened the empire's naval forces, adding to further stress to the dying Sultan Bayezid II. Ezio made it to Cappadocia in March 1512, where he hunted down the Byzantine restoration fighters using a list given to him by a dying Barleti, finishing what he had started.